1. Field of the Invention
The present invention relates to a color cathode ray tube apparatus and a method for manufacturing a color cathode ray tube apparatus, and more specifically it relates to a color cathode ray tube apparatus that is suitable for mounting of a deflection yoke thereto, and a method of manufacturing the above-noted color cathode ray tube apparatus.
2. Description of Related Art
A color cathode ray tube apparatus 41 of the past, as shown in FIG. 16 and FIG. 17, is made up of a color cathode ray tube 42 and a deflection yoke 51. The color cathode ray tube 42 is made up of a panel part 43, onto the inside surface of which is formed a phosphor film 43a, a funnel part 47, which includes a shadow mask structure 46 that includes a shadow mask 44 and a frame 45, and a neck part 48, which houses an electron gun structure 50 that emits 3 electron beams.
An electron beam 50a is deflected by a magnetic field from the deflection yoke 51, passes through the shadow mask 44, and causes light to be emitted by the phosphor film 43a, thereby displaying an image on the panel screen.
The phosphor film 43a on the inside surface of the panel part 43 is formed by phosphors for the three primary colors, red, green, and blue, and in order to cause these phosphors to emit light, an electron gun structure 50, which includes three cathodes that emit an electron beam 50a, in an in-line arrangement, is housed within the neck part 48.
In order to deflect the three electron beams 50a that are emitted from the electron gun structure 50 in the horizontal direction and the vertical direction, a deflection yoke 51, which includes a horizontal deflection coil 51a and a vertical deflection coil 51b that generate a magnetic field, is attached to the region of the joint between the funnel part 47 and the neck part 48.
The magnetic field that is generated by the deflection yoke deflects the electron beams 50a so as to display a desired image on the screen.
The deflection electrical power of the color cathode ray tube apparatus 41 is largely governed by the horizontal deflection electrical power of the deflection yoke 51. This horizontal deflection power PH is established by the following equation, which expresses this deflection power as a function of the inner diameter Dc of the envelope inner surface of the deflection coil 51a and the length Lc of the deflection coil 51a that forms the deflection yoke 51, the accelerating potential Eb applied to the electron gun 50, the frequency fH of the horizontal deflection coil, and the horizontal deflection angle xcex8H of the electron beam 50a.
PHxe2x88x9dfHxc3x97Dcxc3x97Ebxc3x97sin2 (xcex8H/2)/Lcxe2x80x83xe2x80x83(1)
From the above-noted relationship, it can be seen that the making of the horizontal deflection power PH small is determined by the accelerating potential Eb that is applied to the electron gun structure 50, the length Lc of the horizontal deflection coil 51a and the inner diameter Dc of the envelope thereof.
If the accelerating potential Eb is made small, the velocity of electrons which impinge on the phosphor film 43a of the panel part 43 is made small, so that the focus characteristics of the image formed with a reduced intensity worsen.
In a usual color cathode ray tube apparatus 41, the accelerating potential Eb that is applied to the electron gun structure 50 is 18 kV or greater, and is usually approximately 25 kV. Note also that it is not desirable to make the length Lc of the horizontal deflection coil 51a large, as this makes the overall length of the color cathode ray tube apparatus 41 long, so that making the inner diameter Dc of the envelope surface small requires that the outer diameter of the neck part 48 be made small.
The making of the outer diameter of the neck part 48 small means that the outer diameter of the electron structure 50 housed therewithin would be made small, resulting in an increase in spherical aberration in the electron lens, this causing a deterioration in the focussing characteristics of the image.
For example, in accordance with Ludwig von Seidel""s aberration theory, for a spherical aberration S1, a koma aberration S2, an astigmatism S3, an electron beam distance from the tube axis of Ya, and an electron gun structure radius of r, the following relationships obtain.
S1xe2x88x9d(Ya/r)2
S2xe2x88x9d(Ya/r)2
S3xe2x88x9d(Ya/r)2
From the above relationships, by making the radius r of the electron gun structure 50 small, these aberrations S1, S2, and S3 increase, the result leading to a deterioration in the focussing characteristics.
If the outer diameter of the electron gun structure 50 is increased as much as possible, so that it approaches the inner diameter of the neck part 48, when a high voltage is applied sparking can be caused between the electron gun structure 50 and the neck part 48.
Because of this, in setting various parameters in the desire to obtain the best possible image, an accompanying increase in the deflection power occurs.
In recent years, color cathode ray tube apparatuses, and particularly for use as terminal displays for personal computers and other data equipment, are experiences demands for not only larger size, decreased thickness, higher intensity, and greater resolution, but also for a reduction in energy consumption.
To satisfy these market requirements, for example with regard to power consumption, in view of the above-noted equations, a method that can be envisioned is that of making any one of the horizontal deflection frequency fH, the envelope surface inner diameter Dc, the accelerating potential Eb, and the horizontal deflection angle xcex8H small, or one of making the length Lc of the horizontal deflection coil large.
However, with the increased application of color cathode ray tube apparatus for displays, there have been increasing demands from the marketplace with regard to functional items such as increased size, thinness, high intensity, high resolution and the like, as well as with regard to quality, it has become impossible to satisfy these demands by merely pursuing extensions of existing technologies.
That is, the above-noted horizontal deflection frequency fH, the envelope surface inner diameter Dc, the accelerating potential Eb and the horizontal deflection angle xcex8H all become large, this leading to a trend to an increase in the horizontal deflection power PH.
This being the situation, one approach is to accommodate this by the accelerating potential Eb that is applied to the electron gun structure 50, the length Lc of the horizontal deflection coil 51a, and the inner diameter Dc of the envelope thereof, which are adjustment factors.
For example, there has been a proposal for achieving operation with a small deflection power by making the boundary part of the funnel part and the neck part narrower than the outer diameter of the neck (refer to the Japanese Unexamined Patent Publication (KOKAI) No. 48-90673).
However, by making the outer diameter of the neck large so that the above-noted boundary part is relatively narrower, not only is a power savings not achieved, but also this proposal lacks practical usability, because of the increased difficult of attaching the deflection yoke.
Accordingly, in view of the drawbacks in the prior art as described above, a major object of the present invention is to provide a color cathode ray tube apparatus with a reduced power consumption, without sacrificing image quality.
A particular object of the present invention is to provide a color cathode ray tube apparatus in which the neck part is made of two parts having different outer diameters, a deflection yoke being disposed at a par thereof that has the smaller diameter.
Another object of the present invention is to provide a method of manufacturing a color cathode ray tube apparatus that includes the formation of a neck part having different outer diameters, and a method of attaching a deflection yoke.
Yet another object of the present invention is to provide a color cathode ray tube apparatus which, by the formation of the funnel part as a quadrangular pyramid shape, an improvement is obtained in the attachment of the deflection yoke to the color cathode ray tube.
In addition, an object of the present invention is to provide a color cathode ray tube apparatus which, by a proposed change in the shape of the deflection that has a reduced inner diameter of the envelope surface that is formed by the horizontal deflection coil of the deflection yoke, the degree of design freedom is improved, without causing a deterioration in the focussing characteristics, thereby enabling a great reduction in power consumption.
To achieve the above-noted objects, the present invention is a color cathode ray tube apparatus which is formed by a color cathode ray tube that has a panel part, onto the inside surface of which is formed a phosphor film for emission of three primary colors, a funnel part that has a funnel-shaped inclination, the expanded-size aperture side of which is joined to the above-noted panel part, and a neck part that is joined to the reduced-size aperture side of the funnel and which houses a electron gun structure that is arranged in in-line manner and which emits three electron beams that cause the phosphor film to emit light, and a deflection yoke which causes the deflection of the electron beams in the color cathode ray tube, wherein the neck part has a main part in which is housed the electron gun structure and a straight-tube reduced-diameter part having an outer diameter that is smaller than the main part of the neck part, and which is joined to the funnel part, and the deflection yoke having a horizontal deflection coil and a vertical deflection coil, a surface that is coaxial with and parallel to a longitudinal axis of said reduced diameter part and a opening inclined surface being formed on the inner envelope surface, these being disposed along the outer periphery of the straight-tube reduced-diameter part of the neck part and the funnel-shaped inclination of the funnel part.
More specifically, one end of the deflection yoke is fixed to one end of the outer peripheral surface main part of the neck part, the inner surface of the envelope of the deflection yoke being formed by the horizontal deflection coil so as to be coaxial and parallel to a longitudinal axis of said reduced diameter part, the inner diameter thereof being the same as or smaller than the outer diameter of the reduced-diameter part of the neck part.
The outer diameter of the reduced-diameter part of the neck part is preferably at least smaller than the tolerance of the outer diameter of the main part, and equivalent to or larger than the substantial inner diameter of the electron gun or outermost peripheral diameter of the electron beam trace, thereby enabling the swiveling of the deflection yoke, so as to facilitate adjustment.
More specifically, this is set to within the range of 95% to 75%, and the length of the reduced-diameter part is set at a length by adding an amount of play equivalent to the amount of movement for Integrated Tube Component (ITC) adjustment to the deflection yoke parallel surface length.
Additionally, the present invention is a color cathode ray tube apparatus is a color cathode ray tube which is formed by a color cathode ray tube that has a panel part on which is formed a phosphor film and a neck part that houses an electron gun structure, these being joined together by a funnel part, the neck part having a main part that houses the electron gun structure and a reduced-diameter straight-tube shaped part that is narrower than the main part, a connecting part between the above-noted parts, and being provided with a step part that is for the purpose of positioning the deflection yoke.
The connecting part of the neck part should be as short as possible, preferably should have a length of 10 mm or less.
Additionally, the present invention is a method of manufacturing a color cathode ray tube apparatus which is formed by a color cathode ray tube that has a panel part on which is formed a phosphor film and a neck part that houses an electron gun structure, these being joined by a funnel part, and a deflection coil that is attached thereto in the region of the joint between the neck part and the funnel part, this manufacturing method having a step of preparing two bulb members having differing outer diameters so as to be coaxial with the axis of the neck tube at the connection part of the neck part, and a step of butting these materials up against one another and fusing them together.
If necessary, it is possible to form a flare in the end of one of the two bulb members having differing outer diameters so that its outer diameter is nearly the same as the outer diameter of the other bulb member, this flare being butted up against and fused to the end of the other bulb member, thereby improving the accuracy and facilitating this joining process.
The present invention is also a method of manufacturing a color cathode ray tube apparatus that is formed by a color cathode ray tube that has a panel part on which is formed a phosphor film and a neck part that houses an electron gun structure, these being joined by a funnel part, and a deflection coil that is attached thereto in the region of the joint between the neck part and the funnel part, this manufacturing method having a step of preparing two bulb members having differing outer diameters so as to be coaxial with the axis of the neck tube at the connection part of the neck part, a step of inserting the bulb member having the smaller outer diameter into one end of the bulb member having the larger outer diameter by a prescribed length, and a step of fusing together the above-noted parts that are inserted and overlapping.
In addition, the present invention is a method of manufacturing a color cathode ray tube apparatus in which the deflection yoke is divided into a plurality of deflection coils, and preferably one in which it is assembled from a two parts, a horizontal deflection coil and a vertical deflection coil. More specifically, it is a method of manufacturing an improved color cathode ray tube apparatus in which the deflection yoke is formed from a dual horizontal deflection coil, held in sandwich fashion from top and bottom and a dual vertical deflection coil, held in sandwich fashion from left and right via a bobbin.
Another specific example of the present invention provides a color cathode ray tube apparatus that is formed by a color cathode ray tube that has a panel part, on the inner surface of which is formed a phosphor film for emitting light of three primary colors, a funnel part that has a funnel-shaped inclination and one of apertures of which is joined to said panel part, and a neck part that is joined to another aperture of said funnel part and which houses an in-line arranged electron gun structure that emits three electron beams which cause said phosphor film to emit light, and a deflection yoke which is disposed in the region of the joint between the funnel part and the neck part, and which causes deflection of the electron beams of the cathode ray tube, the neck part being formed by a main part that houses the electron gun structure and a reduced-diameter part that has a diameter that is smaller than the main part, the funnel part being formed as a quadrangular pyramid, and the deflection yoke being formed along the outer peripheral surface of the reduced-diameter part of the neck part and the outer surface of the quadrangular pyramid part of the funnel.
In this case, the deflection yoke is fixed via a wedge-shaped mounting fixture having an L-shaped inner surface that is matched to the outer shape of the quadrangular pyramid part.